Vacuum breaker



G. F. CARLSON 2,898,931

VACUUM BREAKER 2 Sheets-Sheet v1 1% www 11E; K\%-, E 1 QN Aug. 11, 1959 Filed Sept. 7, 1956 if! MIMIMWNIMIMNMWIIHW Illlll 11| 'lik'.l'l.

Aug. 11, 1959 G. F. CARLSON VACUUM BREAKER 2 snets-sneet 2 Filed sem.` 7, 1956 VACUUM BREAKER Gilbert F. Carlson, Skokie, lll., assignor to Bell & Gossett Company, Morton Grove, lll., a corporation of Illinois Application September 7, 1956, Serial No. 608,547

Claims. (Cl. 137-207) My invention relates to a vacuum breaker for use in facilitating the drainage of a tank forming part of a closed system.

For illustrative purposes, the tank to be drained will be considered as the usual compression tank in a closed hot water heating system. The function of a compression tank in such a system is to provide a cushion for expansion surges of the water without loss thereof below a predetermined system pressure. For this purpose, the tank is partially lled with Water above which is trapped a mass of air which provides the cushion-factor. Under some conditions, the tank becomes completely or almost completely filled with water so that the air cushion is lost and it becomes necessary to drain the tank preparatory to the entrapment of a new air mass.

Generally speaking, drainage is now effected through a simple drain valve, or a valve which includes separate air and water passages, either of these Valves being connected directly to the tank. However, use of these drain valves requires the closing of a valve between the tank and boiler so that the water in the tank is isolated from the water in the system. If the latter valve were not closed, it would be necessary to either completely drain the system, or to a level just below the compression tank, to insure a suicient drainage thereof. The principal objections to these generally standard methods of drainage are the time required, about thirty minutes or more for a thirty gallon tank equipped with an ordinary drain valve, and the comparative inaccessibility of the isolating valve in many installations.

It is therefore one object of the invention to provide a vacuum breaker for the tank forming part of a closed system which enables the tank to be generally emptied through the primary drain cock of the system, or through a drain valve attached to the tank and connected to a drain pipe or hose of appropriate length, without entailing an inordinate loss of water from the system.

A further object is to provide a vacuum breaker of the character indicated which is constructed and arranged to act as a visual signal indicating that the tank has been sufficiently emptied and dictating that the primary cock or drain valve should be closed.

A further object is the provision of a method of draining such a tank by the use of the primary drain cock of the system or a drain valve on the tank and a signal which indicates when the tank is empty, or partially emptied to any desired amount.

These and further objects of the invention will be set forth in the following specification, reference beingy had to the accompanying drawings, and the novel means by which the objects are elfectuated will be definitely pointed out in the claims.

In the drawings:

Fig. l is a schematic elevation of a typical, closed, hot water heating system incorporating the vacuum breaker. Y

, Figs. 2, 3 and 4 are fragmentary sections of the compression tank in Fig. l showing the general sequence of rates Patent ice Figs. 2, 3 and 4, respectively, showing the same position sequences assumed by a modified form of the vacuum breaker. Fig. 9 is an enlarged, sectional view of the modified breaker in the position shown in Fig. 7.

Fig. 10 is a fragmentary, sectional view to reduced scale of a compression tank equipped with one form of the vacuum breaker and a common type of drain valve.

Referring to Fig. 1, there is schematically shown a typical, closed, hot water heating system including a boiler 10 which is fired in the usual way, either automatically or manually, supply and return pipes 11 and 12, respectively, leading to and from radiators 13, a circulating pump 14 in the return pipe 12 which is responsive in the conventional manner to space heating demands, a flow control valve 15 in the supply pipe 11 whose opening is determined by pump pressure, and a standard drain cock 16 connected to the bottom of the boiler 10.

A compression tank 17 is positioned above the boiler 10 and in the arrangement shown connects by a pipe 18 with the supply pipe 11 on the intake side of the valve 15, although the pipe 18 may connect directly with the boiler as an equivalent construction. The improved signal and vacuum breaker, generally indicated by the numeral 19, is mounted in the lower part of and extends within the tank 17 The construction detail of the breaker 19 is shown in Fig. 5 to which reference will now be made. The lower wall portion of the tank 17 is extruded inwardly at 20 and internally threaded to receive a plug 21 having an axial passage 22 extending therethrough, a part of this passage being enlarged and threaded to receive a screw 23. The end of the screw 23 which normally extends within the passage 22. is perforated at 24 to receive one end of a wire 25 whose free portion is angularly related to the adjacent part of the wire to provide a prong 26. The wire 25 is preferably made of springy material, such as stainless steel spring wire, so that the prong 26 is biased towards the angular position relative to the adjacent part of the wire 25. The remainder of the wire 25 extends freely through the passage 22 for anchorage connection to a float 27 within the tank 17. The clearance relation between the passage 22 throughout the length thereof and the wire 25 is such that when the breaker 19 occupies the position shown in Fig. 5, air may ow freely through the passage 22 into the tank 17.

During normal operation of the system shown in Fig. 1, the screw 23 is threaded in the plug 22, the prong 26 having been collapsed towards the wire 25 for movement through the passage 22. The breaker 19 is then in the position shown in Fig. 2 with the oat 27 in the upper portion of the tank 17 Assuming that the tank requires drainage, being substantially full of water as shown in Fig. 2, the drain cock 16 is opened and water is discharged from the system until the pressure gage 28 on the boiler 10 registers zero or atmospheric pressure. It will be apparent that the pressure in the tank 17 will be less than atmospheric by an amount equal -to the static head between the tank and boiler.

At Zero reading of the gage 28, the screw 23 is removed frorn the plug 21 and pulled downwardly until the prong 26 can swing away from the wire 25. The buoyancy of the float 27 then moves the breaker 19 upwardly until the upper end of the prong 26 engages the lower end of the plug 21 when the breaker 19 is in the position shown in Figs. 3 and 5.

Since the pressure in the tank 17 is then below atmosphere, a-ir flows through the passage 21 and water thereby replaced in the tank 17 is discharged through th'e drain cock 16. As This operation proceeds, the dep-th' ofwater inA the tank 17 decreases Aand the breaker 19 moves downwardly'since any given position thereof is determined by the buoyancy of the oat 27.

After the screw 23 begins dropping, its distance below the plug 21 provides a visual indicator of the extent of tank drainage at any instant. 1f only partial drainage is desired, the drain cock 16 may be closed at the appropriate dropped position of the screw 23 and if full drainage is required, an occasionalpull on the screw 23 to determine when-the breaker 19 is no longer buoyant will serve as an indication of complete drainage. In either situation, the breaker 19 is then restored to the position shown in Fig. 2 and suicient water is added to the system to fill the Vsame in the conventional manner.

It is possible to condition the breaker 19 to automatically stop air ow through the passage 2,2 when the tank 17 is fully drained and hence free drainage through the cock 16 by making the breaker 19 sufficiently heavy to override the total air pressure at the upper end of the passage 22. For this purpose, the lower end of the iloat 27 is frustoconically shaped at 29 for sealing contact with a like shaped seat 30 in the upper end of the plug 21. i

The modified vacuum breaker shown in Figs. 6 to 9, inclusive, and generally indicated by the numeral 31 differs-principally from the breaker 19 in the type of float member. Hence, like parts are designated by like numerals.

.Referring to Fig. 9, the upper end of the wire 25 is secured to the closed end of an inverted cup 32 having a thin wall section, the arrangement being such that when air is trapped within the cup, the latter becomes buoyant in positions such as Figs. 6 and 7 and acts as a iloat. However, whether the cup 32 is buoyant or not, the wire 25 is sufficiently stiff in relation to the weight of the cup to always maintain the latter in an axially vertical position for a purpose presently explained.

Trapping of air in the cup 32 to achieve buoyancy thereof may be achieved when the heating system is first filled. If such buoyancy remains when it becomes necessary to drain the tank 17, the procedure is the same as described in connection with Figs. 2 Vto 4, inclusive.

If for any reason, the air originally trapped within the cup is no longer present when the tank is to be drained, this situation can be readily observed by the operator when the screw 23 is moved to the position shown in Fig. S. The cup 32 then not being buoyant, the breaker 31 Will drop relatively fast due to its weight and when the cup 32 reached the `position shown in Fig. S, it will be held there for a few seconds to enable the inrushing air to displace some of the water within the cup 32 and restore its buoyancy. The breaker is then permitted to rise to the position shown in Fig. 7 and the oating drop of the breaker ensues as described above. Preferably, the reduced portion 33 of the passage 22 is continued to the upper surface of the plug 21 without terminating ina valve seat as in Fig. 5.

The above modilcations are not restricted to use with the drain cock 16 on the boiler 10 as a means of facilitating drainage'oi` the tank 17 and exhibiting a visual signal. Referring to Fig. and considering use of the breaker 19, the bottom of the tank 17 carries a common type of drain valve 34 to` which is attached a drain pipe or hose 35 which depends from the valve 34 and has its delivery end substantially at the elevation of the drain cock 16. When the valve 34 is opened and the breaker 1. A vacuum breaker for facilitating drainage of a tank forming part of a closed, normally pressurized,

liquid system having a normally closed drain opening below the tank comprising a member adapted for detachable mounting outside of and in closing relation to a bottom opening in the bottom of the tank and connected through such bottom opening to a oat Within the tank, the detachment of the member providing through the bottom opening communication between the atmosphere and the tank and the increasing distance of the member from the tank as the float drops when the drain is open providing a visual indicator of the drainage from the tank.

2. A vacuum breaker for facilitating drainage of a tank forming part of a closed, normally pressurized, liquid system having a normally closed drain opening below the tank comprising a member adapted for detachable mounting outside of and in closing relation to a bottom opening in the bottom of the tank and connected through said bottom opening to a oat within the tank, means for holding the member in a detached and temporary position against the upward pull of the oat, the detached position of the member providing communication through the bottom opening between the atmosphere and Vthe tank and the increasing distance of the member from the tank as the float drops when the drain is open providing a visual indicator of the drainage from the tank.

3. The combination of a tank forming part of a closed, normally pressurized, liquid system having a drain opening below the tank comprising a member detachably mounted outside of and in closing relation to a bottom opening in the bottom of the tank, a lioat in the tank, a wire extending through said bottom opening and connecting the member and lioat and including an end prong biased away from the wire adjacent the member, the detachment of the member providing communication between the atmosphere and the tank and the engagement of the prong with the lower part of the tank holding the member in a detached, temporary position against the upward pull of the float, the increasing distance of the member from the tank as the oat drops when the drain is open and the system pressure is zero gage providing a visual indicator of the drainage from the tank.

4. A vacuum breaker for facilitating drainage of a tank having a drain opening below the tank comprising a member adapted for detachable mounting outside of the tank and in closing relation to a 1bottom opening in the bottom of the tank, a float arranged for positioning within the tank and having a connecting element to extend through the bottom opening to connect the lloat and the member, and means carried by the member for engagement with the tank to hold the member in a detached and open position against the upward pull of the float, the increasing distance of the member from the tank as the iioat drops when the drain is open providing a visual indicator of the drainage from the tank.

5. A vacuum breaker for facilitating drainage of a tank forming part of a closed, normally pressurized liquid system having a drain opening below the tank 19 is conditioned as in Figs. 3 and 5, the above indicated comprising a member adapted for detachable mounting outside of the tank and in closing relation to a bottom opening in the bottom of the tank and connected through the bottom opening to the closed wall of an inverted cup disposed within the tank arranged to trap air therein and render the cup buoyant, the detachment of the member providing communication through the bottom opening between the atmosphere and the tank and the increasing distance of the member from the tank as the cup drops when the drain is open providing a visual indicator of the drainage from the tank.

References Cited in the iile of this patent UNTED STATES PATENTS 335,303 Perkins Feb. 2, 1886 1,795,662 McClellan Mar. 10, 1931 2,111,473 Hudson Mar. 15, 1938 UNITED STATES PATENT OFFICE CERTIFICATE OE CORRECTION Patent No 2,898,931 August ll, T959 Gilbert Carlson Patent should read as corrected below.

Column 4, line 9, strike' out "Comunication" and insert the seme after "providing in line 85 same column EL, line 35, after "Comunication" insert m through said bottom opening m.

Signed and sealed this 23rd day of Ifebruary 1960.,

Attest:

KARL Ea AXLINE ROBERT C. WATSON Commissioner of Patents Attesting Ofcer 

